Gas producer with



Aug. 11, 1959 F. PARIS GAS PRODUCER wnn PULSATING'FLOW 2 Sheets-Sheet 1 Filed June 3, 1957 4 m u u l u I Ill/Ill Fee/yco/s IDHE/S Aug. 11, 1959 F. PARIS GAS PRODUCER WITH PULSATING FLOW 2 Sheets-Sh eet 2 Filed June 3, 1957 Eee/vco/s PAW/8 2,899,287 GAS PRODUCER. W HP LS T N FLOW Francois Paris, Garches, France, assignor to Institut de Recherches de la Siderurgie', Saint Germain-en-Laye, France The present invention relates to a gas producer, i.e. to an apparatus for producing a combustible gas of predetermined characteristics starting from, on the one hand, oxygenated or combustive gas, and/ or oxidized gas, and, on the other, from combustible or reducer bodies.

A main object of the present invention is to provide a gas producer of smaller dimensions than those at present in use, and also to employ the same apparatus, without any modification of importance, with widely differing fuels, for example: fuel oil or pulverized coal, or even simultaneously with several fuels. Moreover, the gas producer in accordance with the invention will commence operation instantaneously and will be capable of producing, as desired, gases partly or completely burnt, or even of transmitting free oxygen.

Another main object of invention is to provide a gas producer with pulsating flow which comprises'a source of pulsating gas leading to a reaction chamber and also means for introducing into this chamber at 'leas t one substance capable of combining chemically with said gas, in such a manner thatsaid substance, having been thoroughly agitated by the pulsating flow, enters into chemical combination, in particular with the pulsating gas, to produce a combustible gas. i

In accordance with a feature of the invention, the source of pulsating gas provides an oxidizing or combustion causing gas and the substance introduced into the reaction chamber is combustible, i.e. is a reducing agent.

In accordance with a further feature of the invention, the source of pulsating gas provides gaseous combustion products at a hi h temperature and the substance introduced into the reaction chamber is combustible, i.e. is a reducing agent.

For example, the source of ignited gas might be the exhaust from a suitably regulated piston engine or a valve distributor applied to a source of carbon dioxide at a high temperature.

According to a further feature, the source of pulsating ignited gas is a pulsating combustion chamber or a pulse jet engine providing the gaseous combustion products at a high temperature, which gas is reduced by a fuel introduced into the chamber receiving the pulsating flow issuing from said source.

The invention further relates to an embodiment comprising one or more of the following features:

(a) The reaction chamber comprises a device for introducing additional oxidizing of combustion causing product;

(1)) An ignition device for the reaction is placed in the reaction chamber;

(c) The oxidizing product as it is fed, is utilized for cooling the walls of the pulsating combustion chamber;

2,899,287 Sgfitfis Patfint c Patented u 11, 1 959 2 over the hot walls of the exhaust pipe supplying the gases to the reaction chamber from the pulsating source;

(f) The exhaust outlet for each pulsating source is extended by a convergent-divergent ejector and the oxidizing product, and/or additional fuel, is introduced by suction through said ejector;

g) The apparatus comprises a tube surrounding one or more than one pulse jets arranged longitudinally and separated from the tube and from each other by'spaces through which the oxidizing product circulates before it is utilized in the pulse jets or in the reaction chamber.

Such pulse jets, which are known per se, comprise essentially a mechanical or aerodynamic non-return valve and an exhaust pipe arranged on opposite sides'of the reaction chamber proper. Their manner of working may be described as a regular automatic cycle operating as follows: oxidizing product drawn in through the valve, combustion with approximately constant volume in the chamber, and expulsion at high velocity of the gases burnt on the exhaust pipe, the frequency being in general some .30 to per second.

It has been observed'that, as gases to which a pulsating movement has been imparted emerge from an exhaust pipe and enter a tube or cavity of larger section, considerable turbulence is produced and there is excellent and instantaneous mixing not only with the gases contained in the tube or cavity but also with any body in a sufficiently fluid or divided state introduced into the path of the exhaust. l

As described above, the fuel is introduced into the tube or cavity in question, preferably into the very path of the pulsating exhaust carbon dioxide at high temperature.

The practice is already known of obtaining gas producers by using pulse jets, but'the fuel is introduced in such cases into-the source of pulsating gas or into the combustion chamber itself, in general simply by augmenting the supply of combustion fuel considerably beyond what is required for combustion. Such a construction reduces considerably the range of variations of pressure and of mechanical energy produced by the apparatus, which, moreover, becomes less stable and more difiicult to regulate.- According to the present invention, which also employs a'pulse jet, this latter conserves all its energy, which then produces at the outlet of the exhaust pipe the great turbulence required.

This turbulence employedby the invention is so great that it permits bringing to reaction at this point a new quantity of oxygen amounting even to several'times that which was ignited-in the pulse jet; and also the additional quantity of fuel selected to'obtain thedesired composition of gas- Y 1 .,Thus, as'co'mpared with the former system, not only does the pulse jet itself receive a much greater fuel supply of air since its functioning is not disturbed, but in addition its improved efliciency in terms of energy enables quantities of fuel to be involved in the reaction which are greatly in excess of this primary'quantity. Indeed, since the energy-producing combustions of the pulse jet are not dampenedby an excess of fuel, these conserve all their vigor, which enables the apparatus to draw in a maximum quantity-of oxygen.

Other objects; features and advantages of the invention will be apparent during the course of the following de scription; P

In the accompanying drawings forming a part of this application:

Fig. 1 is 'a longitudinal section in diagrammatic form ofa gas producer'according to the invention;

Fig.2 is a similar view of an embodiment of'this' gas producer; 1, r

Fig. 3 is a longitudinal section in diagrammatic form of a further embodiment of the gas producer; and

Fig. 4 is a similar view of a third embodiment.

Referring'now to Fig. l, the reaction chamber 1 comprises an exhaust outlet 2, and inlet port 3, a fuel feed pipe 4 and an ignition device 5 which in this case is an electric spark-plug connected to a source of high-tension electric current (not illustrated).

The fuel, for example, a liquid, is conveyed from a tank 6 to the point 4, for example, by providing suitable pressure in the tank 6; the rate of feed is regulated by a valve 7. The discharge point 4 must be in the vicinity of the inlet port 3 in the chamber 1.

The inlet port 3 is the exhaust pipe of a pulsating or periodic source of gas. In the present case, for example, this gas is atmospheric air conveyed through the tube 8 by a compressor (not illustrated) the supply being interrupted periodically by a valve 9 actuated by a rotating cam 10. It is manifest that any other means for providing a pulsating gas might be employed.

The manner of working is as follows: each pulsation of air through the port 3 produces in the chamber 1 a vortex formed by the deflection of the currents of air on contacting the atmosphere within the chamber. This vortical effect thoroughly mixes the air with part of said atmosphere and with the fuel introduced through the feed pipe 4, the duration of this mixing action not exceeding the duration of one exhaust pulsation.

The reaction is then ignited by the spark-plug 5 and generally yields suflicient heat to become self-igniting after the apparatus has heated for a few seconds.

The frequency of the exhaust pulsations through the port 3 is dependent upon the dimensions and rate of feed of the device; it may vary from one to one hundred per second according to whether the apparatus is a very large one or quite small.

One advantageous embodiment of the gas producer, of which the chief elements have been briefly described above, is illustrated in Fig. 2. In this figure, there is shown a refractory heat-insulated tube 11, closed at one extremity 12 and connected by the other extremity 13 to the tube 14.

The device comprises two chambers 15 and 16 divided by a cross-wall 17 which forms support for the exhaust tube 18 of the pulse jet which passes through it. The other extremity of the pulse jet supported on the arms 19 comprises a non-return valve 20 which permits the air introduced into the chamber 15 through the manifold 21 to enter the pulse jet but prevents or restricts its escape during combustion.

The fuel required for these combustions arrives through the injection pipe 22 actuated by the pump 23.

The second chamber 16 comprises a further air tube 24 which may simply be a member of the manifold 21, and a further fuel supply pipe 25 gravity-fed from a fuel tank but which may alternatively be fed from the pump 23.

The turbulence in the chamber 16 enables the feed pipe 25 to be provided with medium-atomizing orifices or even non-atomizing orifices, in the path of the exhaust gases from the tube 18.

The manner of working is as follows: on starting, the air tube 24 can be closed by the throttle 26 and the fuel supply 25 by means of the stop-cock 27. The pulse jet is supplied with air through 21 and with fuel at 22 in suitable proportions and starts immediately provided the air is hot enough and the fuel well pulverized or atomized. Otherwise, the first explosion may be produced by the spark-plug 28 supplied with high-voltage electric current from a device of known type. The throttle 26 and stop-cock 27 can then be opened. The fuel introduced at 25 first, reduces to the state of carbon monoxide the carbon dioxide contained in the blasts of exhaust gas issuing from 18 and its excess reacts ;with the air introduced at 24. The whole is very rapidly mixed to form a homogeneous gas, the composition of which is determined solely by the temperature and the relative quantities of the constituents introduced, according to the equalizing reactions between these constituents. The final temperature may be regulated by influencing the temperatures of the air supplied at 21 and 24. To avoid excessive heating of the walls of the pulse jet, the air entering at 21 will always be at a fairly low temperature except perhaps at the moment of starting. In addition, the walls are cooled outwardly by circulation of air from 21 and 24 around the pulse jet. Additional cool ing can be effected by conveying at least part of the fuel intended for the chamber 16 directly to the wall of the tube 18 by means of the nozzle 29.

The turbulence in the chamber 16 is so great that the fuel admitted at 25 may be of any kind; it is possible even to change the nature of the fuel whilst the device is inoperation. Moreover, the vibrations imparted by the pulsating action of the exhaust at the pipe 25 are sufficient to ensure a regular flow of all atomized or pulverized fuels.

Due to the energy developed by the pulse jet, the pressure obtaining in the chamber 16 is slightly greater than that of the chamber 15; if the apparatus is intended to operate at approximately atmospheric pressure, the air arriving at 24 will be required to be forced by a ventilator. The arrangement as shown in Pig. 3 enables such a ventilator to be dispensed with.

The apparatus shown in Fig. 3 is similar to the preceding one and the reference numerals therein refer to like elements. In Fig. 3 the cross-wall 17 has been suppressed and an ejector 30 adapted for pulsating fiow is arranged opposite the extremity of the exhaust pipe 18. The purpose of this ejector is to suck in a large quantity of air around the pulse jet, thus preventing any return of burnt gases at the entrance to the pulse jet and eliminating the wall 17 of Fig. 2. The wall could however be replaced if it was desired to regulate conveniently the relative amounts of air drawn in through the ejector and through the air-inlet 20 of the pulse jet.

The suction of the ejector moreover, enables the whole unit to be supplied by one single source of air, which may in certain cases be atmospheric air, and improves the recovery in compression energy of the kinetic energy of the pulse jet.

To be more precise, the pressure in the exhaust and reaction chamber 31 may be 2% or 3% above the inlet pressure at 32. This pressure is suflicient in many cases to ensure the flow of gas produced in a heat-exchanger or burner.

A regulating valve 32a is provided in the inlet tube 32. This valve may be sufficient to regulate the relative quantities of air sucked in through the ejector and through the air-inlet 20 of the pulse jet. Indeed, Within very wide limits, the amount of air drawn in at 20 by the pulse jet depends solely on the quantity of fuel fed through 22 into the combustion chamber. Thus, having maintained this quantity of fuel constant, when the air intake 32 is choked by the valve 32a, the quantity of air drawn in by the ejector 30 is reduced without appreciably diminishing the suction at 20.

Furthermore, the suction of the ejector may be employed to facilitate the introduction of fuel to the path of the exhaust gases: the nozzle of 25 is simply placed close to the entrance of the ejector or within the ejector in the vicinity of its suction point. The depression occurring at these points is sufficient to suck in the liquid or pulverized fuel from a tank 33 placed just beneath. The same device can be employed to introduce any substance suitable for the reaction.

Finally, water may be injected either in liquid form or in the form of vapour. This injection may be eifected following the various methods described above of injecting fuel into the reaction chamber.

In Fig. 3, an arrangement is shown at 34 which is intended to cool a delicate point of the apparatus by means of a water jacket supplied from a tube 35. A tube 36 then conveys this water whether vaporized or not, to the desired point which may be located, for example, in the divergent nozzle 30. This water, when injected, will be reduced by the fuel, giving rise to a water gas.

In the case of Figs. 2 and 3, several pulse jets may also be arranged in parallel Within the tube 11, such pulse jets being preferably equipped with aerodynamic valves.

Fig. 4 shows such a modification of the gas producer.

The tube 11 contains two pulse jets which are identical and parallel. These pulse jets are of the aerodynamic valve type, supplied with fuel at 22 as in Figs. 2 and 3, the air-inlet comprising, instead of a spring-controlled valve as in Figs. 2 and 3, an aerodynamic device which enables air to enter the combustion chamber and limits to a great extent the escape of air therefrom. Such a valve here assumes the form of a simple tube 20a, smaller and shorter than the exhaust pipe 18; the most suitable dimensions for this can be found by experiment. The advantage of an aerodynamic valve is that it ensures correct functioning of several pulse jets mounted side-by-side. It has been found that, with mechanical valves, it is very diificult to regulate these so that the pulse jets have exactly the same frequency. In operation therefore irregularities occur and even misfiring, leading to cessation of combustion.

0n the other hand, pulse jets equipped with aerodynamic valves are self-regulated to the same frequency in spite of the slight differences due to tolerances of manufacture; moreover, they tend to adjust themselves into phase-opposition which provides the best means for regulating the functioning of air-suction and expulsion of exhaust gases.

In order to prevent the burnt gases driven back through the aerodynamic valves from mixing with the fresh air in the region of the air-inlet point, these valves are extended by regenerative tube systems which advantageously assume the form of convergent-divergent tubes 37 extended by elbow pieces 38. The tubes are disposed opposite the air-inlets 20a but some little distance therefrom in order to enable fresh air to enter 20a. These regenerative tubes convey gases which are driven back and also a certain quantity of fresh air which has entered between blasts of burnt gases. They are advantageously extended as far as the extremities of the exhaust pipes of the pulse jets in order to reintroduce into the reaction the gases which they contain. Moreover, they can be utilized also by arranging therein the outlet of the fuel supply pipe 25. By this means, the currents circulating in the regenerative tubes can be employed to vaporize or divide the fuel and even to set in motion various reactions, in such a manner as to accelerate subsequent reactions.

In the case where the apparatus is not provided with a ventilator for the circulation of gases, this being elfected solely by the exhaust of the pulse jets, starting of said pulso-reactors could be simply effected by means of small conduits 39 conveying compressed air at a pressure of several kilograms per square centimeter to the combustion chambers, for example, via the aerodynamic valves 20a. A stop-cock 40 enables the compressed air to be cut off as soon as starting has been effected.

Finally, the heat lost through the walls of the tube 11 can be recovered by circulating the intake of fresh air through a double-wall 41 around the tube 11. In this case, the heat-insulation of the tube 11 may be reduced or completely dispensed with, leaving a simple metal tube.

It is to be understood that the forms of the invention herewith shown and described are to be taken as preferred examples of the same, and that various changes in the shape, size, and arrangements of parts may be resorted to without departing from the spirit of the invention, or the scope of the subjoined claims.

What I claim is:

l. A gas producer with pulsating flow comprising in combination a tubular chamber, one inlet port at one end of said tubular chamber, an exhaust outlet at the other end, a pulse jet in said tubular chamber, a non-return valve at the upstream end of said pulse jet, an injection pipe connected to said pulse jet, a pump connected to the injection pipe, a source of fuel connected to said pump, an ejector arranged at the downstream end of the pulse jet in the tubular chamber, a fuel tank, a pipe connected to said fuel tank, the free end of said pipe being located between the pulse jet and the ejector, and a regulating valve in the inlet air port.

2. The combination of claim 1 wherein a water jacket is provided around a part of the pulse jet, a feed water pipe is connected to the water jacket and an exhaust water pipe connects the water jacket and the ejector.

References Cited in the file of this patent UNITED STATES PATENTS 2,750,733 Paris et al. June 19, 1956 

1. A GAS PRODUCER WITH PULSATING FLOW COMPRISING IN COMBINATION A TUBULAR CHAMBER, ONE INLET PORT AT ONE END OF SAID TUBULAR CHAMBER, AN EXHAUST OUTLET AT THE OTHER END, A PULSE JET IN SAID TUBULAR CHAMBER, A NON-RETURN VALVE AT THE UPSTREAM END OF SAID PULSE JET, AN INJECTION PIPE CONNECTED TO SAID PULSE JET, A PUMP CONNECTED TO THE INJECTION PIPE, A SOURCE OF FUEL CONNECTED TO SAID PUMP, AN EJECTOR ARRANGED AT THE DOWNSTREAM END OF THE PULSE JET IN THE TUBULAR CHAMBER, A FUEL TANK, A PIPE CONNECTED TO SAID FUEL TANK, THE FREE END OF SAID PIPE BEING LOCATED BETWEEN THE PULSE JET AND THE EJECTOR, AND A REGULATING VALVE IN THE INLET AIR PORT. 